1. Field of the Invention
The present invention relates to an electric zooming camera equipped with a motor-driven zoom lens, and more particularly to such camera in which zooming is automatically conducted according to predetermined information.
2. Related Background Art
There is already known an electric zoom camera capable of photographing with a constant image magnification. The constant magnification photographing is to record the object in substantially the same size (same photographing magnification) in the photographing frame, regardless of the distance to the object (object distance). An improvement on such camera is disclosed in commonly assigned U.S. Pat. application Ser. No. 301,050 filed Jan. 24, 1989, now U.S. Pat. No. 4,896,177 issued Jan. 23, 1990. That application discloses a camera which, in response to the half-push operation of a shutter release button, detects the object distance by a distance measuring device, then calculates such focal length as to photograph the object with a magnification corresponding to the preselected object size according to thus detected object distance and drives the zoom lens to thus calculated focal length, and, in response to the subsequent full-push operation of the shutter release button, effects the photographing operation.
In the camera of the above-mentioned preceding application, the operator selects a desired one of predetermined object sizes. Since such selectable object sizes are limited, the operator may encounter a case where a desired size cannot be obtained.
In most of the conventional electric zoom cameras, a reversible motor for varying the focal length of the zoom lens is controlled by a manual operation of a see-saw switch provided on the camera body, and the see-saw switch is released to terminate the zooming operation when the image of the object observed in a view finder reaches a suitable size in the viewing field.
In such conventional electric zoom camera, the zooming operation is cumbersome because it has to be started and terminated under the observation of change in size of the object image.